Thread inserts are often utilized in relatively soft materials that are required to repeatedly accept complementary fasteners. Such inserts are generally made from relatively hard material and have an external thread that is engageable in the soft material and an internal thread of relatively smaller pitch diameter that accommodates the complementary threaded fastener. The resultant fastening installation exhibits a significant increase in structural strengh and integrity over installations wherein the fastener is threaded directly into the softer material.
Since locking inserts are an additional structural element in any assembly over and above the threaded aperture in the parent material, installation thereof entails an increase in labor as well as the material cost of the insert. Accordingly, every effort is made to assemble the inserts into complementary holes in a parent material at maximum speed consistent with structural integrity of the completed assembly.
It has heretofore been proposed to drive helical inserts into complementary threaded holes in a parent material by either a hand tool having a nose portion engageable with a tang on the insert or by air powered tools having a driving nose that is engageable with a tang on the insert in the manner similar to the manual tool. Tools for inserting inserts into a relatively soft workpiece are taught in U.S. Pat. Nos. 2,371,622; 2,855,661; 3,093,895; 3,111,751 and 3,579,793. While the power tool of U.S. Pat. No. 3,579,793 materially speeds up the installation process, the limiting factor in speed of application is the feed of the inserts to the tool. While inserts have been mounted on strips for feed to a tool as taught in Swedish Letters Patent No. 341,994, a need has developed in the marketplace for a tool that is positive in operation and that maximizes magazine capacity. The tool should preferably be semi-automatic in nature requiring a single actuation to effect both advancement of an insert into drive position, actuation of the driving tool, and drive of the insert into a complementary hole in a workpiece.